Blinds having horizontal slats, are well known in the window covering art. Such blinds are generally known as "venetian blinds". They usually consist of a head rail, a plurality of thin elongated blind slats, and two or more ladder tapes. The ladder tapes consist of pairs of cords or tapes, with generally transverse rung portions extending between them at spaced intervals. The slats are supported on the rungs of the tapes.
Usually means are provided in the head rail for adjusting the relative positions of the two cords or tapes, so that the slats may be tilted one way or the other, to produce different lighting effects within a building space. However, such blinds are not used exclusively for covering windows, but may also be used for covering other spaces and, in many cases, are used for covering, for example, doorway.
In addition to the ladder tapes, such blinds are usually provided with two or more so-called "raise cords".
The raise cords are simply a pair of cords which pass through openings in the blind slats, and are secured to a bottom rail below the lowermost slat. By suitable pulleys and controls within the head rail, the raise cords may be pulled so as to raise all of the slats up until they are lying closely adjacent in a stack underneath the head rail, thereby leaving the window or other space substantially unobstructed.
Many different makes of such blinds are available on the market, and have been available for many years. In the great majority of cases, such blinds incorporate blind slats made of thin sheet metal, usually sheet aluminum. The aluminum may be coated with a wide variety of different paints or other surface finishes, so as to give customers the widest possible choice when selecting such blinds, to suit the decor of the home or building which they are furnishing. Blind manufacturers are, therefore, obliged to stock large quantities of rolls of strip metal, coated with different finishes, and must then be able to select the appropriate strip for a customer's order to manufacture a blind or blinds on a custom basis.
This is naturally somewhat time consuming, and increases the cost of the blind. Certain customers, in fact, require blinds in which slats are incorporated having several different colors, so that when they are lowered down the different colored slats are arranged in groups, and in effect form bars of color across a window space. This poses much more serious difficulties to the manufacturer. The manufacturer must then manufacture the blind not simply of one color of stock, but any one blind may require to be manufactured of several different colors of stock. This additional complication naturally still further increases the cost of blinds of this type.
A further factor in the manufacture of such blinds is that each blind must be substantially custom-made so as to fit the width and height of a particular window space. The manufacturer must therefore be able to select slats of a particular length, cut them off in a predetermined number suitable for the manufacture of that blind, and then assemble them with their ladder tapes and raise cords.
One of the factors adding to the difficulty of this type of manufacture is the fact that the openings for the raise cords are usually and desirably located a more or less standard distance from each end of the blind. Where blinds are made in which the slats in one blind are longer than the slats in another blind, then the punching of these holes at a predetermined distance from each end of each slat presents a still further problem. Equipment for punching such holes must, therefore, either depend almost entirely on relatively primitive hand labor, or alternatively, if automatic machinery is used, its adjustment may become of critical difficulty, requiring highly skilled operators. In the past, all of these factors have been fully appreciated by manufacturers, and machines of various different designs have been proposed for the purpose of making such blinds, but with varying degrees of success. Some machines are capable of only relatively restrictive application, and are not suitable for making blinds with multiple colors. Other machines are of such a design that the adjustment in the length of the blind slats from one customer to another, is excessively slow and laborious and requires much skilled labor to accomplish.
However, the equipment proposed and designed and used in the past has worked reasonably well, although somewhat slowly and laboriously, at least when producing blinds of a single color, and preferably in standard lengths.
However, in recent years, consumers have demanded blinds with slats of various different widths. Thus it is now almost universal throughout the industry that venetian blinds shall be available with slats having either a one inch, or a three-quarter inch, or a half-inch width. Generally speaking, the prior art design of machines would accommodate only one strip of slat material at a time. Consequently, if it was desired to change from one color to another, or if it was desired to change from one width of blind slat to another, it was necessary to stop the machine, change the coil of strip metal, and make various other adjustments and changes in the tooling on the machine, before production could be resumed.
For all of these various reasons, it is clearly desirable to provide a machine which is substantially self-adjusting to different lengths of blind slats, and which is capable of accepting two or more different colored metal strips for producing different colored slats in the same blind, and which is alternatively capable of accepting metal strips of different widths, for producing blinds having slats of different widths, and which is capable of changing over from one length of blind slat to another with a minimum of manual intervention, and which is capable of changing over from one color to the other with a minimum of manual intervention, and which is alternatively capable of changing over from one width of slat to the other with a minimum of manual intervention.
Preferably, such a machine will be controlled by a central processing unit, capable of receiving commands for the manufacture of a whole series of blinds, one after the other, with a minimum of intervention from an operator who essentially will simply input instructions and then supervise the operation of the machine as it carries out its functions on its own, substantially without further manual intervention.